Water and electrolyte balance studies of birds showing "wet droppings"

Renal compensation for cecal loss in Gambel's quail (Callipepla gambelii)

Some studies have implicated the avian digestive cecae as important sites of water and solute reclamation working in concert with the lower intestine and the kidneys as part of an integrated osmoregulatory system. In Gambel's quail (Callipepla gambelii), we studied compensatory adjustments in renal function on days 6-7 and 16-17 following ligation of cecae. Plasma osmolality (Posm) varied significantly between groups with sham-operated birds (Cs), with an average (Posm) of 348 mOsm/kg H2O and quail with ligated cecae (Cx) having a (Posm) of 355 mOsm/kg H2O. We detected no change in the rate of glomerular filtration (GFR) between experimental and control groups either shortly after cecectomy or after 16-17 d following surgery. Regression analysis of GFR and urine flow rate (V) showed that Cx birds had a significantly lower V at a given GFR than did controls, evidence that Cx quail absorbed more fluid in their renal tubules. Increased fluid reabsorption was apparently driven by an enhanced reabsorption of sodium. Indeed, sodium excretion was lower in Cx quail as compared to sham-operated birds. On days 6-7, Cx quail drank more water than Cs birds, but by days 16-17 drinking rates were similar. At the end of the experiments, Cx quail showed a proliferation of microvilli along the apical membrane of the rectum, an adjustment consistent with the idea that the rectum alters its absorption capacity to adjust for the loss of cecal function.

Physiological evaluation of diuresis in commercial broiler breeders

A physiological investigation on an outbreak of diuresis syndrome in commercial broiler breeder hens was carried out. Daily water consumption increased 4-fold and daily manure wet weight increased two-fold in affected hens. 2. The syndrome did not have a genetic basis. It was associated with kidney dysfunction which, once acquired, was not alleviated by changing the diet, the drinking water, or the environment. Diuresis ceased when water intake was restricted and returned when water was again made freely available. 3. The syndrome was not caused by nephrogenic diabetes insipidus or diabetes mellitus. Key changes in kidney function associated with diuresis included: increased urine flow, decreased urine osmolality, reduced glomerular filtration rates, increased fraction of the glomerular filtration rate excreted as urine and decreased urinary hydrogen ion concentrations. 4. Preliminary histopathological findings and the physiological patterns of kidney dysfunction indicated that the diuresis syndrome was associated with permanent kidney damage, probably caused by the Arkansas strain of infectious bronchitis virus.

Water and electrolyte transport by the avian ceca

In galliform birds with well developed ceca, these are functionally important components of the lower intestinal complex, which is capable as a whole of substantial, hormone-regulated homeostatic modification of mixed urine and intestinal luminal fluid before final excretion. Active Na+ transport drives Na-linked absorption of water and Cl- and secretion of K+; there are also lesser Na-independent components of the latter fluxes. These transport processes are appropriately enhanced by dehydration, Na depletion, or exogenous aldosterone.

Effect of dietary calcium levels near the time of sexual maturity on water intake and excreta moisture content

Three trials were conducted to investigate the effect of dietary calcium on water balance of leghorn pullets. Trial 1 involved introduction of a 4% calcium layer diet at 112, 123, 134, or 144 days of age. Introducing the layer diet early had an early but transitory effect on water intake (P less than .05) and absolute quantity of excreta moisture, although the pattern of percentage excreta moisture was not clearly defined. In a second trial, birds were moved to laying cages at 105 days, with diet change from 1 to 4% calcium occurring at 112 or 142 days. When the layer diet was offered at 112 days, percentage excreta moisture was higher from 113 to 142 days, although no difference was seen after this time. In a final experiment, introduction of a 4% calcium layer diet at either 112 or 133 days of age resulted in higher percentage excreta moisture at four measurement periods to 245 days of age, although this effect was significant only at 147 days (P less than .05). These results suggest there is a transitory effect of dietary calcium on water intake and excreta moisture content. This affect may be of concern within controlled environment buildings and with certain manure-handling systems. In commercial situations, such dietary changes are often confounded with increased dietary protein concentration, another factor known to influence water balance in pullets.

Cecae of desert quail: importance in modifying the urine

The importance of the digestive ceca in the modification of ureteral urine was evaluated in conscious, unrestrained desert quail. Cecaectomized (Cx) birds took in slightly more food and water and excreted more solids and water than did sham operated controls. The percent utilization of food for the Cx birds was 76 and 79% for the sham operated controls. Urate output was 47 ml/kg day for Cx and 41 ml/kg day for the sham operated controls. Water content of the excrement was 90% for the Cx and 85% for the sham operated controls. There was a slight but insignificant increase in uric acid excretion in the droppings of cecaectomized birds.

Salt and water excretion by birds: the lower intestine as an integrator of renal and intestinal excretion

1. In the fowl, the small intestine is important for net absorption of Ca2+ and K+, but not for Na+ nor water (in this and several other species). 2. Net water absorption in birds with large saccate caeca occurs in caeca greater than rectum greater than coprodeum, but net Na+ absorption (an active process motivating other absorptive functions) occurs in rectum less than caeca and coprodeum. 3. Interspecific variability and the scarcity of comparative studies militate against broad, well-founded generalisations in this subject.